A new site called pwnedlist.com lets users check to see if their email address or username and associated information may have been compromised. The site currently allows users to search through nearly five million emails and usernames that have been dumped online. It doesnt store the username, email address and password data itself; instead, it records a cryptographic hash of the information and then discards the plaintext data. It is growing at a rate of about 40,000 new compromised accounts each week.”]
Source: https://krebsonsecurity.com/2011/11/are-you-on-the-pwnedlist/